Tissue irradiation units are well known from current technological advances. To achieve their aim, the patient is placed on a table in an isocenter of the irradiation device so his/her tissue can be irradiated. The irradiation device is equipped with a radiation source that generates radiation, which will eventually be guided to one or even several radiation heads located within the device. Generally, a device rotates the radiation heads around the object to be irradiated in such a way that the beams always reach the target volume sequentially from various directions. The target volume receives a relatively large radiation dose in this way, while the healthy surrounding tissue is protected. These known devices have the disadvantage that the precise rotation of the radiation heads is difficult to carry out from the technical viewpoint owing to the size of the masses to be moved.
In order to simplify a tissue irradiation device, EP 1 311 322 B1 suggests the firm arrangement of numerous radiation heads within a housing. What that invention foresees is a common radiation source for all radiation heads, in which case a radiation splitter splits the radiation to the various radiation heads. After the splitting, the individual beams are in each case deflected several times by a beam guidance system until they are finally guided to the radiation heads, which are largely arranged in the shape of a ring around the tissue to be irradiated. In this design, the arrangement of the radiation heads leads to a relatively large housing size.